Activation of the Ras signal transduction pathway indicates a cascade of events that have a profound impact on cellular proliferation, differentiation, and transformation. Raf kinase, a downstream effector of Ras, is a key mediator of these signals from cell surface receptors to the cell nucleus (Lowy, D. R.; Willumsen, B. M. Ann. Rev. Biochem. 1993, 62, 851; Bos, J. L. Cancer Res. 1989, 49, 4682). It has been shown that inhibiting the effect of active ras by inhibiting the raf kinase signaling pathway by administration of deactivating antibodies to raf kinase or by co-expression of dominant negative raf kinase or dominant negative MEK, the substrate of raf kinase, leads to the reversion of transformed cells to the normal growth phenotype (see: Daum et al. Trends Biochem. Sci. 1994, 19, 474-80; Fridman et al. J. Biol. Chem. 1994, 269, 30105-8. Kolch et al. (Nature 1991, 349, 426-28) have further indicated that inhibition of raf expression by antisense RNA blocks cell proliferation in membrane-associated oncogenes. Similarly, inhibition of raf kinase (by antisense oligodeoxynucleotides) has been correlated in vitro and in vivo with inhibition of the growth of a variety of human tumor types (Monia et al., Nat. Med. 1996, 2, 668-75). Thus, small molecule inhibitors of Raf kinase activity are important agents for the treatment of cancer (Naumann, U.; Eisenmann-Tappe, I.; Rapp, U. R. Recent Results Cancer Res. 1997, 143, 237; Monia, B. P.; Johnston, J. F.; Geiger, T.; Muller, M.; Fabbro, D. Nature Medicine 1996, 2, 668).
Inhibition of p38 has been shown to inhibit both cytokine production (eg., TNFα, IL-1, IL-6, IL-8) and proteolytic enzyme production (eg., MMP-1, MMP-3) in vitro and/or in vivo. The mitogen activated protein (MAP) kinase p38 is involved in IL-1 and TNF signaling pathways (Lee, J. C.; Laydon, J. T.; McDonnell, P. C.; Gallagher, T. F.; Kumar, S.; Green, D.; McNulty, D.; Blumenthal, M. J.; Heys, J. R.; Landvatter, S. W.; Stricker, J. E.; McLaughlin, M. M.; Siemens, I. R.; Fisher, S. M.; Livi, G. P.; White, J. R.; Adams, J. L.; Yound, P. R. Nature 1994, 372, 739).
Clinical studies have linked TNFα production and/or signaling to a number of diseases including rheumatoid arthritis (Maini. J. Royal Coll. Physicians London 1996, 30, 344). In addition, excessive levels of TNFα have been implicated in a wide variety of inflammatory and/or immunomodulatory diseases, including acute rheumatic fever (Yegin et al. Lancet 1997, 349, 170), bone resorption (Pacifici et al. J. Clin. Endocrinol. Metabol. 1997, 82, 29), postmenopausal osteoperosis (Pacifici et al. J. Bone Mineral Res. 1996, 11, 1043), sepsis (Blackwell et al. Br. J. Anaesth. 1996, 77, 110), gram negative sepsis (Debets et al. Prog. Clin. Biol. Res. 1989, 308, 463), septic shock (Tracey et al. Nature 1987, 330, 662; Girardin et al. New England J. Med. 1988, 319, 397), endotoxic shock (Beutler et al. Science 1985, 229, 869; Ashkenasi et al. Proc. Nat'l. Acad. Sci. USA 1991, 88, 10535), toxic shock syndrome, (Saha et al. J. Immunol. 1996, 157, 3869; Lina et al. FEMS Immunol. Med. Microbiol. 1996, 13, 81), systemic inflammatory response syndrome (Anon. Crit. Care Med. 1992, 20, 864), inflammatory bowel diseases (Stokkers et al. J. Inflamm. 1995-6, 47, 97) including Crohn's disease (van Deventer et al. Aliment. Pharmacol. Therapeu. 1996, 10 (Suppl. 2), 107; van Dullemen et al. Gastroenterology 1995, 109, 129) and ulcerative colitis (Masuda et al. J. Clin. Lab. Immunol. 1995, 46, 111), Jarisch-Herxheimer reactions (Fekade et al. New England J. Med. 1996, 335, 311), asthma (Amrani et al. Rev. Malad. Respir. 1996, 13, 539), adult respiratory distress syndrome (Roten et al. Am. Rev. Respir. Dis. 1991, 143, 590; Suter et al. Am. Rev. Respir. Dis. 1992, 145, 1016), acute pulmonary fibrotic diseases (Pan et al. Pathol. Int. 1996, 46, 91), pulmonary sarcoidosis (Ishioka et al. Sarcoidosis Vasculitis Diffuse Lung Dis. 1996, 13, 139), allergic respiratory diseases (Casale et al. Am. J. Respir. Cell Mol. Biol. 1996, 15, 35), silicosis (Gossart et al. J. Immunol. 1996, 156, 1540; Vanhee et al. Eur. Respir. J. 1995, 8, 834), coal worker's pneumoconiosis (Borm et al. Am. Rev. Respir. Dis. 1988, 138, 1589), alveolar injury (Horinouchi et al. Am. J. Respir. Cell Mol. Biol. 1996, 14, 1044), hepatic failure (Gantner et al. J. Pharmacol. Exp. Therap. 1997, 280, 53), liver disease during acute inflammation (Kim et al. J. Biol. Chem. 1997, 272, 1402), severe alcoholic hepatitis (Bird et al. Ann. Intern. Med. 1990, 112, 917), malaria (Grau et al. Immunol. Rev. 1989, 112, 49; Taverne et al. Parasitol. Today 1996, 12, 290) including Plasmodium falciparum malaria (Perlmann et al. Infect. Immunit. 1997, 65, 116) and cerebral malaria (Rudin et al. Am. J. Pathol. 1997, 150, 257), non-insulin-dependent diabetes mellitus (NIDDM; Stephens et al. J. Biol. Chem. 1997, 272, 971; Ofei et al. Diabetes 1996, 45, 881), congestive heart failure (Doyama et al. Int. J. Cardiol. 1996, 54, 217; McMurray et al. Br. Heart J. 1991, 66, 356), damage following heart disease (Malkiel et al. Mol. Med. Today 1996, 2, 336), atherosclerosis (Parums et al. J. Pathol. 1996, 179, A46), Alzheimer's disease (Fagarasan et al. Brain Res. 1996, 723, 231; Aisen et al. Gerontology 1997, 43, 143), acute encephalitis (Ichiyama et al. J. Neurol. 1996, 243, 457), brain injury (Cannon et al. Crit. Care Med. 1992, 20, 1414; IIansbrough et al. Surg. Clin. N. Am. 1987, 67, 69; Marano et al. Surg. Gynecol. Obstetr. 1990, 170, 32), multiple sclerosis (M. S.; Coyle. Adv. Neuroimmunol. 1996, 6, 143; Matusevicius et al. J. Neuroimmunol. 1996, 66, 115) including demyelation and oligiodendrocyte loss in multiple sclerosis (Brosnan et al. Brain Pathol. 1996, 6, 243), advanced cancer (MucWierzgon et al. J. Biol. Regulators Homeostatic Agents 1996, 10, 25), lymphoid malignancies (Levy et al. Crit. Rev. Immunol. 1996, 16, 31), pancreatitis (Exley et al. Gut 1992, 33, 1126) including systemic complications in acute pancreatitis (McKay et al. Br. J. Surg. 1996, 83, 919), impaired wound healing in infection inflammation and cancer (Buck et al. Am. J. Pathol. 1996, 149, 195), myelodysplastic syndromes (Raza et al. Int. J. Hematol. 1996, 63, 265), systemic lupus erythematosus (Maury et al. Arthritis Rheum. 1989, 32, 146), biliary cirrhosis (Miller et al. Am. J. Gasteroenterolog. 1992, 87, 465), bowel necrosis (Sun et al. J. Clin. Invest. 1988, 81, 1328), psoriasis (Christophers. Austr. J. Dermatol. 1996, 37, S4), radiation injury (Redlich et al. J. Immunol. 1996, 157, 1705), and toxicity following administration of monoclonal antibodies such as OKT3 (Brod et al. Neurology 1996, 46, 1633). TNFα levels have also been related to host-versus-graft reactions (Piguet et al. Immunol. Ser. 1992, 56, 409) including ischemia reperfusion injury (Colletti et al. J. Clin. Invest. 1989, 85, 1333) and allograft rejections including those of the kidney (Maury et al. J. Exp. Med. 1987, 166, 1132), liver (Imagawa et al. Transplantation 1990, 50, 219), heart (Bolling et al. Transplantation 1992, 53, 283), and skin (Stevens et al. Transplant. Proc. 1990, 22, 1924), lung allograft rejection (Grossman et al. Immunol. Allergy Clin. N. Am. 1989, 9, 153) including chronic lung allograft rejection (obliterative bronchitis; LoCicero et al. J. Thorac. Cardiovasc. Surg. 1990, 99, 1059), as well as complications due to total hip replacement (Cirino et al. Life Sci. 1996, 59, 86). TNFα has also been linked to infectious diseases (review: Beutler et al. Crit. Care Med. 1993, 21, 5423; Degre. Biotherapy 1996, 8, 219) including tuberculosis (Rook et al. Med. Malad. Infect. 1996, 26, 904), Helicobacter pylori infection during peptic ulcer disease (Beales et al. Gastroenterology 1997, 112, 136), Chaga's disease resulting from Trypanosoma cruzi infection (Chandrasekar et al. Biochem. Biophys. Res. Commun. 1996, 223, 365), effects of Shiga-like toxin resulting from E. coli infection (Harel et al. J. Clin. Invest. 1992, 56, 40), the effects of enterotoxin A resulting from Staphylococcus infection (Fischer et al. J. Immunol. 1990, 144, 4663), meningococcal infection (Waage et al. Lancet 1987, 355; Ossege et al. J. Neurolog. Sci. 1996, 144, 1), and infections from Borrelia burgdorferi (Brandt et al. Infect. Immunol. 1990, 58, 983), Treponema pallidum (Chamberlin et al. Infect. Immunol. 1989, 57, 2872), cytomegalovirus (CMV; Geist et al. Am. J. Respir. Cell Mol. Biol. 1997, 16, 31), influenza virus (Beutler et al. Clin. Res. 1986, 34, 491a), Sendai virus (Goldfield et al. Proc. Nat'l. Acad. Sci. USA 1989, 87, 1490), Theiler's encephalomyelitis virus (Sierra et al. Immunology 1993, 78, 399), and the human immunodeficiency virus (HIV; Poli. Proc. Nat'l. Acad. Sci. USA 1990, 87, 782; Vyakaram et al. AIDS 1990, 4, 21; Badley et al. J. Exp. Med. 1997, 185, 55).
A number of diseases are thought to be mediated by excess or undesired matrix-destroying metalloprotease (MMP) activity or by an imbalance in the ratio of the MMPs to the tissue inhibitors of metalloproteinases (TIMPs). These include osteoarthritis (Woessner et al. J. Biol. Chem. 1984, 259, 3633), rheumatoid arthritis (Mullins et al. Biochim. Biophys. Acta 1983, 695, 117; Woolley et al. Arthritis Rheum. 1977, 20, 1231; Gravallese et al. Arthritis Rheum. 1991, 34, 1076), septic arthritis (Williams et al. Arthritis Rheum. 1990, 33, 533), tumor metastasis (Reich et al. Cancer Res. 1988, 48, 3307; Matrisian et al. Proc. Nat'l. Acad. Sci., USA 1986, 83, 9413), periodontal diseases (Overall ct al. J. Periodontal Res. 1987, 22, 81), corneal ulceration (Burns et al. Invest. Opthalmol. Vis. Sci. 1989, 30, 1569), proteinuria (Baricos et al. Biochem. J. 1988, 254, 609), coronary thrombosis from atherosclerotic plaque rupture (Henney et al. Proc. Nat'l. Acad. Sci., USA 1991, 88, 8154), aneurysmal aortic disease (Vine et al. Clin. Sci. 1991, 81, 233), birth control (Woessner et al. Steroids 1989, 54, 491), dystrophobic epidermolysis bullosa (Kronberger et al. J. Invest. Dermatol. 1982, 79, 208), degenerative cartilage loss following traumatic joint injury, osteopenias mediated by MMP activity, tempero mandibular joint disease, and demyelating diseases of the nervous system (Chantry et al. J. Neurochem. 1988, 50, 688).
Because inhibition of p38 leads to inhibition of TNFα production and MMP production, inhibition of mitogen activated protein (MAP) kinase p38 enzyme provides an approach to the treatment of the above listed diseases including osteoporosis and inflammatory disorders such as rheumatoid arthritis and COPD (Badger, A. M.; Bradbeer, J. N.; Votta, B.; Lee, J. C.; Adams, J. L.; Griswold, D. E. J. Pharm. Exper. Ther. 1996, 279, 1453).
Vasculogenesis involves the de novo formation of blood vessels from endothelial cell precursors or angioblasts. The first vascular structures in the embryo are formed by vasculogenesis. Angiogenesis involves the development of capillaries from existing blood vessels, and is the principle mechanism by which organs, such as the brain and the kidney are vascularized. While vasculogenesis is restricted to embryonic development, angiogenesis can occur in the adult, for example during pregnancy, the female cycle, or wound healing.
One major regulator of angiogenesis and vasculogenesis in both embryonic development and some angiogenic-dependent diseases is vascular endothelial growth factor (VEGF; also called vascular permeability factor, VPF). VEGF represents a family of isoforms of mitogens existing in homodimeric forms due to alternative RNA splicing. The VEGF isoforms are highly specific for vascular endothelial cells (for reviews, see: Farrara et al. Endocr. Rev. 1992, 13, 18; Neufield et al. FASEB J. 1999, 13, 9). VEGF expression is induced by hypoxia (Shweiki et al. Nature 1992, 359, 843), as well as by a variety of cytokines and growth factors, such as interleukin-1, interleukin-6, epidermal growth factor and transforming growth factor.
To date, VEGF and the VEGF family members have been reported to bind to one or more of three transmembrane receptor tyrosine kinases (Mustonen et al. J. Cell Biol., 1995, 129, 895), VEGF receptor-1 (also known as flt-1 (fins-like tyrosine kinase-1)), VEGFR-2 (also known as kinase insert domain containing receptor (KDR); the murine analogue of KDR is known as fetal liver kinase-1 (flk-1)), and VEGFR-3 (also known as flt-4). KDR and flt-1 have been shown to have different signal transduction properties (Waltenberger et al. J. Biol. Chem. 1994, 269, 26988); Park et al. Oncogene 1995, 10, 135). Thus, KDR undergoes strong ligand-dependant tyrosine phosphorylation in intact cells, whereas flt-1 displays a weak response. Thus, binding to KDR is a critical requirement for induction of the full spectrum of VEGF-mediated biological responses.
In vivo, VEGF plays a central role in vasculogenesis, and induces angiogenesis and permeabilization of blood vessels. Deregulated VEGF expression contributes to the development of a number of diseases that are characterized by abnormal angiogenesis and/or hyperpermeability processes. Regulation of the VEGF-mediated signal transduction cascade will therefore provide a useful mode for control of abnormal angiogenesis and/or hyperpermeability processes.
Angiogenesis is regarded as an absolute prerequisite for growth of tumors beyond about 1-2 mm. Oxygen and nutrients may be supplied to cells in tumor smaller than this limit through diffusion. However, every tumor is dependent on angiogenesis for continued growth after it has reached a certain size. Tumorigenic cells within hypoxic regions of tumors respond by stimulation of VEGF production, which triggers activation of quiescent endothelial cells to stimulate new blood vessel formation. (Shweiki et al. Proc. Nat'l. Acad. Sci., 1995, 92, 768). In addition, VEGF production in tumor regions where there is no angiogenesis may proceed through the ras signal transduction pathway (Grugel et al. J. Biol. Chem., 1995, 270, 25915; Rak et al. Cancer Res. 1995, 55, 4575). In situ hybridization studies have demonstrated VEGF mRNA is strongly upregulated in a wide variety of human tumors, including lung (Mattern et al. Br. J. Cancer 1996, 73, 931), thyroid (Viglietto et al. Oncogene 1995, 11, 1569), breast (Brown et al. Human Pathol. 1995, 26, 86), gastrointestional tract (Brown et al. Cancer Res. 1993, 53, 4727; Suzuki et al. Cancer Res. 1996, 56, 3004), kidney and bladder (Brown et al. Am. J. Pathol. 1993, 1431, 1255), ovary (Olson et al. Cancer Res. 1994, 54, 1255), and cervical (Guidi et al. J. Nat'l Cancer Inst. 1995, 87, 12137) carcinomas, as well as angiosacroma (Hashimoto et al. Lab. Invest. 1995, 73, 859) and several intracranial tumors (Plate et al. Nature 1992, 359, 845; Phillips et al. Int. J. Oncol. 1993, 2, 913; Berkman et al. J. Clin. Invest., 1993, 91, 153). Neutralizing monoclonal antibodies to KDR have been shown to be efficacious in blocking tumor angiogenesis (Kim et al. Nature 1993, 362, 841; Rockwell et al. Mol. Cell. Differ. 1995, 3, 315).
Overexpression of VEGF, for example under conditions of extreme hypoxia, can lead to intraocular angiogenesis, resulting in hyperproliferation of blood vessels, leading eventually to blindness. Such a cascade of events has been observed for a number of retinopathies, including diabetic retinopathy, ischemic retinal-vein occlusion, retinopathy of prematurity (Aiello et al. New Engl. J. Med. 1994, 331, 1480; Peer et al. Lab. Invest. 1995, 72, 638), and age-related macular degeneration (AMD; see, Lopez et al. Invest. Opththalmol. Vis. Sci. 1996, 37, 855).
In rheumatoid arthritis (RA), the in-growth of vascular pannus may be mediated by production of angiogenic factors. Levels of immunoreactive VEGF are high in the synovial fluid of RA patients, while VEGF levels are low in the synovial fluid of patients with other forms of arthritis of with degenerative joint disease (Koch et al. J. Immunol. 1994, 152, 4149). The angiogenesis inhibitor AGM-170 has been shown to prevent neovascularization of the joint in the rat collagen arthritis model (Peacock et al. J. Exper. Med. 1992, 175, 1135).
Increased VEGF expression has also been shown in psoriatic skin, as well as bullous disorders associated with subepidermal blister formation, such as bullous pemphigoid, erythema multiforme, and dermatitis herpetiformis (Brown et al. J. Invest. Dermatol. 1995, 104, 744).
Because inhibition of KDR leads to inhibition of VEGF-mediated angiogenesis and permeabilization, KDR inhibitors will be useful in treatment of diseases characterized by abnormal angiogenesis and/or hyperpermeability processes, including the above listed diseases.